<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="../react资料_stu//依赖包/react.development.js"></script>
    <script src="../react资料_stu//依赖包/react-dom.development.js"></script>
    <script src="../react资料_stu//依赖包/babel.min.js"></script>
    <script src="../react资料_stu//依赖包/prop-types.js"></script>
</head>

<body>
    <div id="app"></div>
    <script type="text/babel">
    /* 
      创建Refs
        Refs 是使用 React.createRef() 创建的，并通过 ref 属性附加到 React 元素。在构造组件时，会把当前书写ref的DOM交给创建的iptEle保管,放在它的current属性上
        创建一个Refs只能存放一个DOM
    */
        class Parent extends React.Component {
            iptEle=React.createRef();
            render() {
                return (
                    <div>
                        <input type="text" ref= {this.iptEle}/>
                        <button onClick={this.handle}>点我弹出用户输入的内容</button>
                        <input type="text" onChange={this.iptChangeHandle} placeholder='表单修改后弹出输入的内容'/>
                    </div>
                )
            }
            handle = () => {
                console.log(this);
                const { value } = this.iptEle.current;
                alert(value)
            }

            iptChangeHandle=(e)=>{
                console.log(e.target.value);
            }
        }
        ReactDOM.createRoot(document.getElementById('app')).render(<Parent />)
    </script>
</body>

</html>